Pressure fluid power amplifier



2,524,6&2

d. 3, w50 E. G. s'rAUDE PRESSURE FLUID POWER AMPLIFIER 3 Sheets-Sheet 1 Filed NOV. 26, 1.947

Q Haude W INVENTOR MNHN m HNA Filed Nov. 26, 1947 E. G. STAUDE PRESSURE FLUID POWER AMPLIFIER 3 Sheets-Sheet 2 ,INVENTOR Edwin Szauce @new ATTORW CL 3, 1950 E,l G, STAUDE 2,524,682

PRESSURE FLUD POWER AMPLIFIER Filed Nov. 26,l 1947 3 Sheets-Sheet 3 Il? /l -66 INVENToR \ZZ Edwin Saude a l W3 M23/kw Patented Oct. 3, 1950 UNITED STATES PATENT OFFICE PRESSURE FLUID POWER AMPLIFIER Edwin G. Staude, Minneapolis, Minn. Application November 26, 194,7,v VVserial No. 738,245L

My invention relates particularly to a power amplifier operated by fluid pressure, adapted for' the application of power for work performance generally, but which is applicable especially for the operation in the steering of automotive vehicles such, for example, as automobiles.

The important purpose in a fluid power amplier should be to obtain dependable instant response, as free as possible from failure of operation, while having economy in operation, low cost of construction, light weight and relatively small size. The power amplifier made in accordance with my invention definitely fulfills these exacting requirements.

Care has been exercised to avoid `all loose flexible connections, without sacrificing any desirable feature of the construction.

An exceptionally short distance has been attained, also, between the static power applied and the work to be performed, in my power amplier. Further I have found that high fluid pressures, for instance 500 p. s. i., flow 'hrougn a passage at much greater velocity than a considerably lower pressure and, therefore, for the same quick response a much smaller passage area can be used in accordancewith my invention. Accordingly, have found that a inch round inside diameter passage is ample for the fluid pressure intake to supply, with instant response, a 4% square inch total vane area, when operating on an average vane radius of 31/2 inches. Also, there may be used four canes,

each of the same being, for instance, 11/2 incheswide by 3A, inches high. This means that such a unit, for example at 500 p. s. i., although any other pressure may be used, will deliver a torque ofv 7875 inch pounds on the output shaft;

There may be, for example, two forms of this structure for power amplification to suit different conditions. One of' these is where the pressure isv retained, thus locking the vanes when the valve controlling means is released and in which pressure will be released only if the valve controlling means is moved in the opposite direction. This form is desirable for most air craft controls where the servo is required to follow the movement of the controlling valve and keep the control locked at all times against independent movement. The other form is where the Ipressure on the vanes is released instantly when the` effort exerted on the valve controlling means is released. This latter form is particularly useful in power steering where castering of the front wheels is desirable to permit the car to again assume 1a straight ahead position automatically. This is accomplished by normally keeping both outlet ports open and only closing either one of the outlet valves beforethe fluid pressure enters the particular passage leading thereto. This is accomplished by making the 16 Claims. (Cl. 121-41) valve stems on the outlet valves a little longerJ and' the valve stems on the inlet passage a little shorter so that motion by the valve controlling memberY will act to close the particular outlet passage before the corresponding inlet passage opens.

Further objects to to provide an enlarged plunger to reduce back pressure andy to provide effectiveI sealing means on the fluid intake.

Further objects will appear from the detailed description of my invention hereinafter.

While'my invention is capable of embodiment in many different fonms, for the purpose of illustration I have shown only certain forms of my invention inthe accompanying drawings, in which- Fig, 1 is a vertical 4cross section of my four vane uid pressure power amplifier;

Fig. 2 is a longitudinal vertical section thereof taken on line 2-2 of Fig. 1;

Fig. 3 is a longitudinal vertical section therecf taken on line 3-3 of Fig. 1;

Fig. 4 is a horizontal section thereof taken on line ia-, of Fig. 2;

Fig. 5 is an elevational view of one wall of the power amplifier, partly in section, showing the manner of sealing the Ipressure fluid against seepage;

Fig. 6 is a vertical sectional detail taken on lineG--B of Fig. 2;

Fig. 7 is a vertical sectional detail taken on line 'I-l of Fig. 2;

Fig. 8 is a vertical sectionalV detail taken on line 8-8 of Fig. 2;

Fig. 9 is a vertical sectional detail taken on line 9 9 of Fig. 2; and

Fig. 10 is a vertical cross section of a modified form of the valve :assembly showing a valve mechanism adapted for automatically releasing pressureY when thevalve controlling member is released.

In the drawings, referring first to Figs. 1 to 9, I' have shown side walls I and 2 which form a casing in conjunction with an :annular ring 3 locatedin grooves 4 in the wall I and 5 in the wall 2, and which are secured together by screws and 1.

The screws. 'I also serve to locate and secure in, place chamber dividers 8, each of which is divided transversely into two pieces, for convenience in assembling.

Located between the side walls I and 2 and within the annular ring 3 there is an oscillating member 9 having vanes I0, II, I2 and. I3. Thesel vanesdivide the spaces within the annular ring 3 formed by the chamber dividers 8 into operating chambers. I4, I5, l5, Il, I8, I9, 29 and 2l.

The oscillating member 2 is made in two parts 22'` andb22a. The member 22 is provided with a,

hub 23 and a thin bushing 24.

A roller bearing 25 fits over the hub 23 and is mounted in the wall I. The member 22a is provided with a hub 26 which is supported in a ball bearing 21 mounted in the wall member 2. The bearing 21 is clamped in position by a cap 28 secured by cap screws 29. The usual low pressure fluid sealing ring 38 is also provided. The seepage which accumulates around the bearing 21 passes up through a narrow channel 3| and empties into a passage 32. A similar narrow channel 33 is provided in the Wall member I which also connects any seepage around the bearing 25 with the passage 32 (see Fig. 5). The passage 32 has an arc relief 34, 35 in the wall member I so the passage 32 will not be obstructed as to a fluid outlet36 which connects with the return to the source of supply through connections made with a nipple 31 when the member 9 oscillates (see Fig. A similar relief 38, corresponding to the relief at 35 in the wall member, is provided in the wall member 2. The hub 26 has an extension 39 to which an arm 4I) is secured for attachment of the device to be moved. The arm 46 is provided with a serrated inside which fits over the extension 39 and is secured in position by a clamping bolt 4I. The inlet passage for the iuid under pressure is provided by means of a nipple 42 to a passage 43 which in turn connects with a passage 44. Because of the high pressure, for example of about 500 p. s. i., and in order to reduce seepage as much as possible, I provide rst an arcuate recess 45, 46 in the wall member I (see Fig. 5) and around the recess 45, 46 I form a groove, which groove serves to retain a ringshaped elastic packing ring 41, as, for example, made of rubber or a synthetic rubber substitute. On the opposite side in the-wall member- 2 I provide a similar arcuate recess 48, 49 and around this arc recess 48, 49 I form a groove, which L groove serves to retain a round elastic packing ringA 59. Thearc groove 48, 49 is merely for the purpose of equalizing the pressure in the arc groove 45, 46 and as a precaution against seepage.

I have shown one form of my invention as applied to a standard type of steering mechanism 5I, having the usual type steering shaft 52 operated by the usual hand wheel (not shown) and having a worm gear 53 secured to the steering shaft 52. An anti-friction worm wheel 54 cooperates with the gear teeth of the worm gear 53 and serves to oscillate a member 55 which is part of an output power shaft 56 mounted in bearings 51 and 58. The shaft 56 telescopes into the hub 23 and provides a further bearing in connection with the thin bushing 24. An extension 59 is provided on the end of the shaft 56. This extension has a serrated surface over which lits a valve controlling member 60. The mechanism just described shows how the valve member 68 is controlled by the steering wheel (not shown). A passage 6I connects an annular passage 62 in the oscillating member 22 with the operating chamber I4, a passage 63 connects it with the operating chamber I6, a passage 64 connects it with the operating chamber I8, and a passage 65 connects it with the operating chamber 29. All of these,A thus, connect with the annular passage 62, which when under fluid pressure will cause the unit to operate in an anti-- clockwise direction. For clockwise operation thereof the pressure is directed, instead, through an annular passage 66. In order to separate the two annular passages 6I and 66 I provide an annular plate or ring 61 which is clamped to t 4 between the members 22 and 22a so as to locate the same in a small recess 68, one half of which is in the member 22 and the other half in the member 22a.

Referring to Figs. l, 4, 6, 7, 8 and 9, it will be noted that the ring 61 closes off the passage 6I from the passage 66. Passage connections from the annular passage 66 to the operating chambers are provided by a passage 69 which connects the chamber 2l with the annular passage 66, a passage 10 which connects with the chamber I5, a passagev 1I which connects with the chamber I1, and a passage 12 which connects with the chamber I9 (see Fig. 3). In order to control the ow of the fluid under pressure to the various operating chambers, four poppet valves are provided, which are operable independently of each other, said valves comprising two inlet and two outlet valves, all operated by a single valve controlling member and mounted within a separate assembly unit 13 to facilitate manufacture and assembly. Suitable stops 14 are provided within the member i 3 so that the maximum movement of the valve member 60 will engage the stops 14 and operate the power amplifier manually in the event that the Huid pressure fails. The member 22 is provided with the annular passage 62 and is connected with the inlet and outlet passages as hereinafter described. The annular passage 66 also connects with the fluid pressure inlet passage 44 by a passage 15, 16 to a round chamber 11 which contains a large diameter short plunger or guide 18 on a peripheral tapered flange inlet valve 19. The large diameter of the plunger 18 leaves only a small back pressure area on the adjacent face of the ilange valve 19. The inlet valve 19 blocks the ilow of fluid from the passage 44 through the passage 16 which connects with the chamber 11. On the opposite side of the valve 19 there is a chamber 80 through which a smaller diameter short plunger 8| of the valve 19 passes. The bearing for the smaller diameter plunger 8l is the member 13 and the bearing for the larger diameter plunger 18 is in a sleeve 82 which is pressed into a round bore in the member 13 against a small shoulder for the location thereof. The purpose of the relatively large plunger 16 is to reduce the back pressure against the valve 19 by reducing the area against which pressure against the valve 19 acts to a minimum of approximately not over five pounds, in this example of my invention, depending upon the exposed surface. N0 springs are required to keep any of the valves closed because they all operate against pressure which keeps the valves urged towards their seats. The same reason for the enlarged plungers on the pressure side of the valves applies to all the valves. The valve 19 is raised from its seat by a projection 83 of the valve operating member 69 bearing against the plunger 8i so that fluid under pressure can pass from the chamber through a passage 84 into the annular passage 66 (see Fig. 6). For exhaustingv the fluid from the annular passage 66 I provide a passage 66a (see Fig. 8) connecting the annular passage 66 with a chamber 86. An upper valve 81 blocks the flow of the fluid into a valve chamber 88. The said valve 81 is provided with plunger guides 89 and 99 and the chamber 69 connects with the outlet passage32 by passages 9I and 92. A projection 93 of the valve operating member 69, bearing against the plunger 9G, opens the valve 81 when operated in anti-clockwise direction. The path of the fluid to the annular passage 62 from the inlet passages 44s and 15. is. asfollowsf': A passage 9.4: connects withA a. chamber 95V (see Fig. 2).. The chamber 95 is provided with a valvev 96 which valve has. plunger guidesA 9.1 and 98. The valve 96. controls, the passage of` fluid under pressure toi a. chamber 99:. The chamber 9.9. is connected by a. passage |66. to the annular passage 62 (see Fig..'l..). When the projection 83 of the valve operating member 661 bears against the plunger 98 suiciently to raisethe valve against the fluid pressurenthe'uid flows into the chamber 99 and then through the passage |`into the annular passage 6.2. For exhausting the fluid from the annular passage. 62, a; passage |0| connects. the annular passage 6.2. with a chamber |02 (seeFig. 9). Within the chamber |02 there is. a valve |03 having guide plungers |04 and |05. On the opposite. side of the valve |03 there is a chamber |06 into which lluid can only flow if the valve |03 is raised from its seat by pressure from the projection 93 of the valve controlling member 60, against the plunger |04. The chamber |66 is connected with the outlet passages 32` and 92 by a passage |01. Thevalve member 60 is kept in the. central or neutral position shown in Fig. 2. by two bodies of U-shaped resilient material, such as rubber or a synthetic rubber substitute, |08 and |06a which are packed around projections |09 and I0, respectively, that engage the resilient material the full width of the projection 83 on the Valve controlling member 60. Narrow passages Il and ||2 to low pressure act as vents or breathersv for the plungers 38 and 89 and 91 and |05 (see Figs. 2 and 4). In the vanes, I have shown a round resilient packing |3 between the vane and theY annular ring 3 and a round resilient packing |4 between the spacer 6 and the oscillating member 9. The two oscillating member halves 22 and 22a, together with the member 'I3 located between, are bolted together by bolts ||5y through the vanes and bolts ||6l connecting 4the members 22 and 22a with the member 78 against separate movement. All of the bolts may be secured by riveting or prick punching the ends.

In Fig. l0, which comprises a slight modicationphave shown the valves 81 and |03 in the open position, which is accomplished by providing slightly increased lengths of plungers 90 and |04. and 96 are also slightly shortened to provide some lost motion so that in oscillating thevalve controlling member 60 the valves 8'! and |03 will close before the desired inlet valve opens. The reason for the arrangement shown in Fig. I0 is in order to release the pressure automatically when the valve controlling member 60 no longer follows up, so that for power steering purposes the ground wheels can caster and assume a straight ahead position when the manual steer? .1

ing wheel is released. This releasing feature is practicable particularly in certain installations, because for air craft, the controls must be kept in locked position responsive only tothe position of the valve controlling means` which results from the valve position in Fig. 2. Preferably, there is` always some lost motion between the projection '93 and the plungers 90 and |04 to insure the positive `seating of .the valves 8l and'` |03. There is, however, more lost Vmotion between the projection 83 and the plungers 8| and 98to permit the partial opening of the valve 8l or |03 before the fluid pressure is released by the valve 'E8 or 96, respectively.

The'operation of my device is as follows: For

Plungers. 8| and 9S of the inlet valves 19 means of the extension 59y the valve control.mem.

ber 60 is also moved anti-clockwise, causing the projection 83 to bear against the plunger 98 so as to lift the valve 96 from its seat and permit lluid under pressure to enter the small chamber 99, from which the fluid under pressure flows through the. passage |00 into the annular passage 62 (see Fig. 7). While the fluid under pressure.. in the'annular passage 62 flows down the. passage |0| into the small chamber |02 the projection 93 keeps the valve |03 closed to the outlet passage |67. Therefore, the fluid must ilow out through the passages 6|, 63, 64 and 65 and move the vanes l0, l2 and |3 anti-clockwise.

In order to release the fluid on the opposite side of the vanes the projection 93 is moved to open the valve 8l so the iluid in the chambers I5, il, I9 and 2| can flow out through the passages 69, T56, il and l2 into the annular passage 66 and from there out through the passage 66a into the small valve chamber 83 past the open valve 8T, then into the passages 9| and 92 and out through the passage 32 intoY the return pas.- sages 315i', 35 and 36.

For clockwisek motion the operation is reversed. The valve 87 is opened by movement ofthe projection 83 and the fluid under pressure flows into the small chamber 60, through the passage 84,

into the annular passage 66 (see Fig. 6).

The fluid then ilows down the passage 66a. into the small chamber 86 where it is blocked by the valve 81, thence out through the passages 69, 10, l`| and l2 to move the vanes clockwise.

In this instance, the projection 93 has opened |61' into the passages 92 and 32 and out through the passages 34, 35 and 36.

The slightly modified form shown in Fig. 10 operates in the same manner except that with the outlet valve-operating plungers and |94* being longer than the inlet valve-operating plungers-8| and 88, the fluid pressure is released', automatically so that the ground wheels canA caster and assume a straight ahead position. when the manual steering wheel on the column 52 is released.

While I have described my invention above in detail I wish it to be understood that many changes may be made therein without departing from the spirit of the same.

For example, while I have shown my fluid power amplier as applied for power steering of motor vehicles and as controlled by the usual manually operated steering wheel, it is to be understood that Imay also dispense with this remote control and attach any other form of actuator directly to the shaft 56 so as to control the valve controlling member 66 directly by the manual effort, depending on the purpose for which the servo mechanism is to be used.

The manually operated steering unit to which my invention is applied in the drawings is, for instance, a speed reducing mechanism, and such speed reducing mechanism may, also, be desirable for other power control applications where amplied power output is desired.

I claim:

l. A double acting iluid power amplifier having a source of fluid pressure, a lluid connection "thereto, a plurality of compartments, rotatable walls arranged to be moved by said iluid pressure therein and which are connected together, a lmember connecting said walls to a work performing element, passages leading from the source of fluid pressure to said Walls, plural poppet valves in said passages located inside the path of said walls for controlling the application of said fluid pressure to each of said walls by obstructing the movement of the liquid in said passages and controlling the pressure acting against the walls to cause movement of said walls in the direction desired, and manually operable rotatable means located in the center of said path including reversible valve-operating mechanism operable in either direction from an initial inactive position for operating said valves and controlling the application of said fluid pressure to said movable walls.

2. A double acting iluid power amplifier having a source of fluid pressure, a fluid connection thereto, eight compartments, four rotatable walls arranged to be moved by said fluid pressure so that each wall moves in one of four pairs of said compartments and which are connected together, a member connecting said walls to a Work performing element, passages leading from the source of fluid pressure to said walls, four poppet valves in said passages located inside the path of said walls for controlling the application of said fluid pressure to each of said walls by obstructing the movement of the liquid in said passages and controlling the pressure acting against the walls to cause movement of said walls in the direction desired, and manually operable rotatable means located in the center of said path including reversible valve-operating mechanism operable in either direction from an initial inactive position for operating said valves and controlling the application of said fluid pressure to said movable walls.

3. A double acting fluid power amplifier having a source of fluid pressure, a iluid connection thereto, eight compartments, four rotatable walls arranged to be moved by said fluid pressure so that each wall moves in one of four pairs of said compartments and which are connected together, a member connecting said walls vto a work performing element, passages leading from the source of fluid pressure to said walls, four poppet valves in said passages located inside the path of said walls for controlling the application of said fluid pressure to each of said walls by obstructing the movement of the liquid in said passages and controlling the pressure acting against the walls to cause movement of said walls in the direction desired, manually operable rotatable means located in the center of said path including reversible valve-operating mechanism operable in either direction from an initial inactive position for operating said valves and controlling the application of said fluid pressure to said movable walls, and stationary partitions located between each of said pairs of compartments.

4. A double acting iluid power amplifier having a source of fluid pressure, a iluid connection thereto, a plurality of compartments, rotatable walls arranged to be moved by said fluid pressure therein and which are connected together, a member connecting said walls to a work performing element, passages leading from the source of lluid pressure to said walls, plural poppet valves in said passages located inside the path of :aid walls for controlling the application of said fluid pressure to each of said walls by obstructing the movement of the liquid in said passages and controlling the pressure acting against the walls to cause movement of said walls in the direction desired, and manually operable rotatable means located in the center of said path including reversible rotary valve-operating mechanism with a pair of diametrically opposed yielding stops operable in either direction from an initial inactive position for operating said valves and controlling the application of said fluid pressure to said movable walls.

5. A double acting iluid power amplifier having a source of iluid pressure, a iluid connection thereto, a plurality of compartments, rotatable walls arranged to be moved by said fluid pressure therein and which are connected together, a member connecting said walls to a work performing element, passages leading from the source of fluid pressure to said walls, plural plunger operated poppet valves, having tapered valve flanges, in said passages located inside the path of said walls for controlling the application of said fluid pressure to each of said walls by obstructing the movement of the liquid in said passages and controlling the pressure acting against the walls to cause movement of said walls in the direction desired, and manually operable rotatable means located in the center of said path including reversible valve-operating mechanism operable in either direction from an initial inactive position for operating said valves and controlling the application of said fluid pressure to said movable walls.

6. A double acting fluid power amplifier having a source of fluid pressure, a fluid connection thereto, a plurality of compartments, rotatable walls arranged to be moved by said fluid pressure therein and which are connected together, a member connecting said walls to a work performing element, passages leading from the source of fluid pressure to said walls, plural plunger operated valves, having tapered valve flanges, in said passages located inside the path of said walls for` controlling the application of said fluid pressure to each of said walls by obstructing the movement of the liquid in Vsaid passages and controlling the pressure acting against the walls to cause movement of said walls in the direction desired, and manually operable rotatable means located in the center of said path including reversible valve-operating mechanism operable in either direction from an initial inactive position for operating said valves and controlling the application of said iluid pressure to said movable walls, each of said valve plungers comprising guide plungers on opposite sides of its tapered valve flange, one of which plungers is of small diameter for operation by said valve operating mechanism and the other of which is of larger diameter so as to leave a narrower adjacent portion of the valve flange subject to back fluid pressure than on the other side of said valve ilange.

'7. A double acting fluid power amplifier having a source of fluid pressure, a fluid connection thereto, a plurality of compartments, rotatable walls arranged to be moved by said fluid pressure therein and which are connected together, a member connecting said walls to a work performing element, passages leading from the source of fluid pressure to said walls, plural plunger operated valves, having tapered valve ilanges, in said passages located inside the path of said walls for controlling the application of lksaid fiiuid pressure .to each of said walls 'by v'obstructing the lmovement of the liquid in ysaid passages .and :controlling the pressure facting against'the .walls to cause movement :of said Walls in the direction desired, and .manually `operable Yrotatable fmeans located `in the center of said path .including reversible valve-operating mech- :anism operable in leither direction `from an initial inactive position :for operating said valves and controlling the application-'of said fluid pressure to said movable Walls, each of said valve plungers comprising guide 4plungers on opposite sides of its tapered valve nange, said guide plung- :ers having vlengths not more than the approximate V.diameter of .the 'valve son which they are carried.

8. A double acting fluid power :ampliiier having a source Iof fluid pressure, a iuid connection thereto, a vplurality of compartments, rotatable rwalls .arranged to be moved by said fluid pres- '.-sure therein and which are connected together,

a `member connecting said walls to a work per- .;forming element, passages leading from the source Aof iiuid pressure to said Walls, plural plunger operated valves, having tapered valve `flanges, in said passages located inside the path of said Walls for controlling the :application of said fluid pressure to each of said Walls by obstructing the movement of the liquid in said Apassages and controlling the pressure acting against the -Walls .to cause movement of said walls in the direction desired, and manually operable rotatable means located in the center of said path including reversible valve-operating mechanism operable -in -either direction from an initial inactive position for operating said valves and controlling the application offsaid fluid pressure to said movable Walls, each of said valve plungers comprising guide plungers on Opposite sides Vof its tapered valve flange, one of which plungers is of small diameter for operation Aby said valve operating mechanism and the other of which is .of larger diameter ,so vas to leave a `narrovver adjacent portion of the valve flange subject to back. fluid pressure than ,on the-other side of said valve flange, said guide ,plungers 4,having lengths not more than Athe approximate diameter .of the `valveon which they are carried.

9. A .double acting uid povver amplier `having a source of fluid pressure, a fluid connection thereto, Va plurality of compartments, rotatable Walls arranged to be moved by said uid pressure therein and which .are connected together, a member connecting said Walls to a work 'performing element, passages .leading from the source of fluid pressure to said wall-s, plural plunger operated inlet Yand outlet valves, having tapered valve flanges, in said passages located inside the path of said walls for lcontrolling the .application-of said fluid pressure `to each of -said walls by obstructing the movement of the liquid in said passages and controlling the pressure .act- Y ing against 4the walls to cause .movement of -said Vvvalls in the direction desired, one of which .plungers is also ,for valve operation thereby, and manu- Lally moerablfJ rotatable means located in lthecenter of path 'including reversible valve-operating mechanism operable in either direction from an, initial inactive position for operating sai-d val-ves and controlling the application ofsaid .fluid pressure to said movable walls, 'each of said valve plungers comprising guide plungers on opposite sides of its tapered valve flange, the valve operating outlet valve plungers being longer than the valve operating inlet plungers so as to normally keep the outlet valves open and release the fluid 'member connecting said walls Vto a work performing element, ,passages leading from the source of fluid pressure to said Walls, Iplural plunger operated inlet and outlet valves, having tapered valve flanges, in said passages located inside the path. of :said Walls -for controlling the application of -said fluid -pressure to each of said f Walls by obstructing the movement 'of the liquid in said passages and controlling ythe pressure Yact- Eing against the walls to cause movement of said `Walls in the direction desired, -one of which Iplungers is also 1for -valve operation thereby, and 'manually opera-ble rotatable Ymeans located in the .center 'of said path including reversible 4valve- -operating mechanism operable in either Vdirection from y'an initial inactive position for `operating said valves-and vcontrolling the application of said uid pressure to 'said movable vvalls, .each of `said valve plungers comprising guide plungers on opposite `sides of -its tapered valve ilange, one of which lplungers is of :small diameter Afor operation .by said valve `operating `mechanism and the other'of which-is vof larger-diameterso-as'to leave a narrower adjacent lportion of the valve flange subject to -back Vfluid pressure than on the other side of said valve flange, the valve operating -outlet valve plungers being longer than the valve operating inlet plungers so as to .normally keep the ,outlet valves open and release the `nuid -pressure when lthe manual operating means is released.

11. -A double acting fluid `power amplifier hav- `ing a source of fluid pressure, a fluid connection thereto, .-a plurality of compartments, rotatable walls arranged to 4'be moved by said fluid pressure therein .and which ,are connected together, a member lconnecting said `vvalls to a Work performing element, passages leading from the ysource Aof duid pressure to `said walls, plural plunger .operated inlet `and outlet valves, having `tapered valve flanges, in said passages located inside fthe `path `oi" said walls for controlling the application ofsaid ,fluid pressure to `each'of said xvallslbyobstructing the movement 4of the liquid f insaid passages and-controlling-the pressure act- ,ing against the Walls .to cause movement of said Walls in the direction zdesired, one of which vplungers is ,also for valve operation thereby, Vand `manually operable rotatable means located in `theicenter of .said-.path jincluding reversible valveoperating mechanism 4operable .in either direction from .an initial `inactive position for operat- .ing .said lvalves and .controlling vthe application of .said fluid pressure to said movable walls7 each of said valve plungers .comprising guide plungers on .opposite sides of ,its tapered valve ange, said guide `.plungers having lengths .not more than the .approximate diameter of the valve on whichthey are carried, the valve .operating outlet valve plungers being `longer than the valve operating inlet .plungers so .as to normally keepthe outlet valves open and release ,the `fluid pressure when the manual .operating means is released.

12. ,A .double acting .fluid .power amplifier having a source of viiuid pressure, a fluid connection thereto, a plurality of compartments, rotatable vvalls arranged to be moved by said iiuid pressure therein and which are connected together, a member connecting said walls to a work performing element, passages leading from the source of fluid pressure to said Walls, plural plunger operated inlet and outlet valves, having tapered valve flanges, in said passages located inside the path of said walls for controlling the application of said fluid pressure to each of said walls by obstructing the movement of the liquid in said passages and controlling the pressure acting against the walls to cause movement of said walls in the direction desired, one of which plungers is also for valve operation thereby, and manually operable rotatable means located in the center of said path including reversible valve-operating mechanism operable in either direction from an initial inactive position for operating said valves and controlling the application of said fluid pressure to said movable walls, each of said valve plungers comprising guide plungers on opposite sides of its tapered valve ange, one of which plungers is of small diameter for operation by said valve operating mechanism and the other of kwhich is of larger diameter so as to leave a narrower adjacent portion of the valve flange subject to back fluid pressure than on the other side of said valve flange, said guide plungers having lengths not more than the approximate diameter of the valve on which they are carried, the valve operating outlet valve plungers being longer than the valve operating inlet plungers so as to normally keep the outlet Valves open and release the iluid pressure when the manual operating means is released.

13. A double acting iluid power amplier having a source of fluid pressure, a fluid connection thereto, a plurality of compartments, rotatable walls arranged to be moved by said liuid pressure therein and which are connected together, a member connecting said Walls to a work performing element, passages leading from the source of fluid pressure to said walls, plural poppet valves in said passages located inside the path of said walls for controlling the application of said iiuid pressure to each of said walls by obstructing the movement of the liquid in said passages and controlling the pressure acting against the walls to cause movement of said walls in the direction desired, and manually operable rotatable means located in the center of said path including reversible valve-operating mechanism operable in either direction from an initial inactive position for operating said valves independently of each other and controlling the application of said iluid pressure to said movable walls.

14. A double acting fluid power amplifier having a source of fluid pressure, a fluid connection thereto, eight compartments, four rotatable walls arranged to be moved by said fluid pressure so that each wall moves in one of four pairs of said compartments and which are connected together, a member connecting said walls to a work performing element, passages leading from the source of fluid pressure to said walls, four poppet valves in said passages located inside the path of said wall for controlling the'application of said fluid pressure to each of said walls by obstructing the movement of the liquid in said passages and controlling the pressure acting against the Walls to cause movement of said walls in the direction desired, and manually operable rotatable means located in the center of said path including rel2 versible valve-operating mechanism operable in either direction from an initial inactive position for operating said valves independently of each other and controlling the application of said fluid pressure to said movable walls.

15. A double acting uid power amplier having a source of fluid pressure, a uid connection thereto, stationary walls enclosing partitions forming a plurality of compartments, an oscillating member carrying movable walls arranged to be moved by said fluid pressure therein and which are connected together, a member connecting said walls to a work performing element, passages leading from the source of uid pressure to said walls and therefrom to said oscillating member by a sealed connection, plural valves in said passages for controlling the application of said fluid pressure to each of said walls by obstructing the movement of the liquid in said passages and controlling the pressure acting against the walls to cause movement of said walls in the direction desired, and manually operable means including reversible valve-operating mechanism operable in either direction from an initial inactive position for operating said valves and controlling the application of said uid pressure to said movable walls.

16. A double acting fluid power amplifier having a source of fluid pressure, a fluid connection thereto, stationary walls enclosing partitions forming a plurality of compartments, an oscillating member carrying movable walls arranged to be moved by said fluid pressure therein and which are connected together, a member connecting said walls to a work performing element, passages leading from the source of fluid pressure to said walls and therefrom to said oscillating member by a sealed connection having an arcuate recess containing an enclosing ring-shaped flexible seal,l

plural valves in said passages for controlling the application of said fluid pressure to each of said walls by obstructing the movement of the liquid in said passages and controlling the pressure acting against the walls to cause movement of said Walls in the direction desired, and manually operable means including reversible valve-operating mechanism operable in either direction from an initial inactive position for operating said Valves and controlling the application of said fluid pressure to said movable walls.

EDWIN G. STAUDE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 639,673 Dyblie Dec. 19, 1899 1,301,757 Steffes Apr. 22, 1919 1,385,858 Blasiar July 26, '1921 1,570,097 Sumner Jan. 19, 1926 1,751,276 Karibo Mar. 18, 1930 1,788,378 Bragg Jan. 13, 1931 1,978,667 Breese Oct. 30, 1934 2,376,804 Orshansky May 22, 1945 FOREIGN PATENTS Number Country Date 354,327 Great Britain Aug. 4, 1931 

